Floating Supply Amplifier Circuit for Wide Common-Mode Range
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Solution Overview
Problem
Electronic systems face inefficiencies and increased power requirements due to the need to accommodate large common mode voltages, which can be several times larger than differential signal voltages, leading to higher operational power demands and a trade-off between cost and accuracy.
Innovation Solution
The implementation of a circuit that generates floating supply voltages that track the common mode voltage, allowing amplifiers to operate independently of the common mode voltage, thereby reducing power allocation to it and using lower supply voltages, such as ±2.5 V, which enables the use of standard, high-quality components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed supply voltages are set to accommodate maximum common mode voltage excursions, then the amplifier can handle large common mode voltages, but power consumption increases significantly
Solution Approach 1:
The patent implements dynamic supply voltages that automatically track and follow the common mode voltage level. Instead of using fixed high supply voltages to cover the entire common mode range, the supply voltages dynamically adjust to match the actual common mode voltage plus the required signal swing margin. This dynamic adaptation allows the amplifier to maintain adequate headroom for signal processing while consuming minimal power when common mode voltages are low.
Solution Approach 2:
The patent changes the supply voltage parameters from fixed values to variable values that track the common mode voltage. The supply voltages are modified to be functions of the common mode voltage level, specifically set to common mode voltage plus a margin (e.g., VCM + 2.5V). This parameter change enables the system to adapt power consumption to actual operating conditions while maintaining signal integrity.
2Adaptability or versatility
If high supply voltages are used to accommodate common mode voltage, then the amplifier can process signals with large common mode components, but component quality must be compromised due to cost
Solution Approach 1:
The dynamic supply voltage tracking enables the use of standard-quality components by ensuring that high supply voltages are only applied when actually needed. When common mode voltages are low, the supply voltages are correspondingly lower, allowing standard components to operate within their optimal ranges. This dynamic approach eliminates the need to over-specify components for worst-case scenarios.
Solution Approach 2:
The patent effectively replaces expensive high-voltage components with standard-voltage components that operate dynamically. By using standard-quality components with dynamically adjusted supply voltages, the system achieves the same performance as expensive high-voltage components would provide, but at lower cost and with standard component quality.
3Reliability
If fixed supply voltages accommodate peak common mode voltage, then signal distortion is prevented, but power is wasted during normal operation
Solution Approach 1:
The dynamic supply voltage tracking ensures that supply voltages are always set to the minimum level required to prevent signal distortion. The supply voltages follow the common mode voltage plus a margin, providing exactly the headroom needed for the current signal conditions. This eliminates the power waste associated with using fixed high supply voltages while maintaining reliable distortion-free operation.
Solution Approach 2:
The system uses feedback from the common mode voltage detection to dynamically adjust the supply voltages. The supply voltages are continuously monitored and adjusted based on the actual common mode voltage level, ensuring optimal headroom is maintained without excessive power consumption. This feedback mechanism prevents both distortion and power waste.
Data Source
AI summary
An electronic system generates at least one floating supply voltage, wherein during operation of the circuit the floating supply voltage tracks a common mode voltage of first and second differential input signals. By tracking the common mode voltage, in at least one embodiment, the floating supply voltage adjusts as the common mode voltage changes. Thus, the floating supply voltages can be based upon the peak-to-peak values of the first and second output signals without factoring in the common mode voltage. In at least one embodiment, the electronic system provides the floating supply voltages to an amplifier. The amplifier amplifies the first and second differential input signals and generates differential output signals. A differential sampling circuit samples the differential output signals to cancel the common mode voltage from the differential output signals. In at least one embodiment, an analog-to-digital converter converts the sampled differential output signals into a digital output signal.